GRM Spec E30 project part deux

#1

Just got the latest Grassroots Motorsport mag in the mail today- they’ve got part 2 of their SpecE30 build in there. Haven’t had a chance to look at it yet…

I guess lots of folks are at VIR this weekend.

Bret

#2

You haven’t read it yet?? I tore into the moment I saw it arrived. No mention of the next installment on the back page though. Am waiting with anticipation. This is my first post and will introduce myself. I am Wesley Jones and have just recently stumbled on the SpecE30 series. I have participated in a few HPDEs with NASA-SE and was told about SE30 by my instructor at Road Atlanta a few weeks ago. I have located a '87 325is that looks like a good start and will pick it up next weekend. I have been using my '00 Honda Prelude for DEs and wanted something I could build and not be too afraid of totaling. I will be at Rockingham in a few weeks but plan on using my prelude then just until I get the bimmer checked out and some of the suspension work started. The first DE I hope to run with it will be the second Rockingham event in two months. So I hope to see and talk with all of the SE30 guys in a few weeks at the rock. Wes

#3

Good to hear, Jones.

I’ll be racing at the Rock that weekend. Come by and say hello. Look for the black and red BeerTech car.

JP

#4

Wesley:

Keep us up to date on your progress.

Carter
Spec E30 Administrator

#5

I got the latest GRM yesterday and promptly read it. Per and Scott wrote a very nice article on the safety equipment in Per’s Spec E30 race car.

Their rollcage philosophy was interesting. The cage they went with doesn’t have NASCAR bars and instead uses the side X-bars (similar to rally cars). They made the case that they might be better off (for safety) by having an ungutted door with factory side impact beam than with the NASCAR bars. They reasoned that the door with side impact beam will absorb some of the impact energy and result in less energy transmitted to the cage (and driver) than would be the case if the car had the usual gutted door with NASCAR bars. This also allowed them to keep the window in the driver’s door which is nice. The challenge I have with this is that NASCAR bars will always (unless the cage fails) keep the offending car away from your body while the ungutted door will still deform into the X-bars which are very close to your body (if not actually in contact with it).

How do you guys feel about this? I can see why Per chose the cage style he did but it seems that almost every pro-built race car I see in SoCal uses NASCAR bars. I also realize that NASCAR bars increase the area moment of inertia of the car and hence, it’s stiffness which is good for handling.

Still, it was a good article and I kept on thinking that this car will probably be up for sale next year as the GRM boys change cars more than they change underwear :slight_smile: (no offense guys, you do great work!)

Mike

#6

uh60fixer wrote:

Interestingly, I am at the point in my build process where it is time to install the cage. I had assumed that I was going with the NASCAR bar approach, but after reading the article, I am more inclined to go with the X-bar approach.

#7

They didn’t really put a weight on which factor(s) had the most influence, but also a factor with the NASCAR bars was having to remove the window (and they said the car would be outside hence potential water leak issues).

#8

For a couple of years I have been wishing that all club racing organizations could band some funds together, perhaps partnering with a good university, and do some REAL, customized research on what works (and what doesn’t) in terms of safety equipment in a club racing environment. We could learn so much more about actual loading/energy transfers and the proper ways to manage them.

#9

there is quite a bit of discussion on bimmerforums.com about nascar vs. X-bars.
Almost all racing cars in europe use X-bars.

The theory is that nascar bars, since they are bent, can deform inwards as much as they are bent outwards. X-bars would have to stretch to deform inwards, which is much harder. If you do nascar bars, be sure to tie them together in the middle vertically so the bars don’t just twist on their endpoints and rotate in on you.

True nascar bars (in NASCAR cars) are integrated with the car structure and are quite high and quite low, not just two bars like you see with a lot of so-called nascar bars setups. Oftentimes it is what a pro series mandates vs. personal preference in pro cars. Some series are now mandating nascar plus X bars.

I doubt that nascar vs. X-bars imparts any more structural rigidity.
cheers,
bruce

#10

The old NASCAR frames, they say, were too stiff, and didn’t give enough in an impact. I’m curious what the side impact protection bars on the ‘car of tomorrow’ look like. I believe they filled the door with foam, too.

#11

Still looks similar, but they made it bigger and each side has high impact material. Also the drivers seat has been moved 3 inchs towards the middle.

I will probably go with a X bar setup as my car will not be only for the race track.

#12

I have X-bar, and asked my cage builder to add an additional horizontal bar across the door below the X with a vertical bar to the cross in the X to provide additional stability in the event of a t-bone on Driver’s side.

One "con" of X-bar is that those bars are close to my left arm - on track it hasn’t been an issue, but it’s so close that when casually in the car I find myself resting my arm on it. If I were wider I imagine this would be a problem either from impact deformation or interference with arm movement.

#13

I haven’t gotten this issue yet - my NASA membership just got renewed a month ago, and the GRM subscription hasn’t caught up yet.

BUT, I noticed in the April issue that they put a VW alternator in the car.

Hmmm . . . not sure that is appropriate, is it?

#14

DaveCN wrote:

[quote]I haven’t gotten this issue yet - my NASA membership just got renewed a month ago, and the GRM subscription hasn’t caught up yet.

BUT, I noticed in the April issue that they put a VW alternator in the car.

Hmmm . . . not sure that is appropriate, is it?[/quote]the Alts are made by Bosch